Over 500 Days in the Life of the Photosphere of the Type Iax Supernova SN 2014dt
Over 500 Days in the Life of the Photosphere of the Type Iax Supernova SN 2014dt
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DOI：
10.3847/1538-4357/acd558
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
Y. Camacho-Neves;S. Jha;B. Barna;M. Dai;A. Filippenko;R. Foley;G. Hosseinzadeh;D. Howell
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文献类型：
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作者：
Y. Camacho-Neves;S. Jha;B. Barna;M. Dai;A. Filippenko;R. Foley;G. Hosseinzadeh;D. Howell
Iax 型超新星 (SNe Iax) 是已知最大的一类奇特白矮星超新星，与正常的 Ia 型超新星 (SNe Ia) 不同。 SNe Iax 的独特性质，尤其是它们在极晚时期的强烈光球线，使我们能够对其光谱进行建模，并推导出持久光球层的物理参数。我们提供了 SN Iax 2014dt 从最大光照后 +11 到 +562 天的广泛光谱时间序列，包括 21 个新光谱。我们能够使用 Fink 等人提出的自洽、几乎未改变的爆燃爆炸模型来重现整个时间序列。使用 TARDIS，一种开源辐射传输代码。我们发现SN 2014dt的光球速度在+64天到+148天之间减缓了它的演化，这与我们看到SN 2014dt偏离SNe Ia正常光谱演化（+90到+150天）的阶段紧密重叠。这些时期的光球速度约为 400–1000 km s−1，可能会在喷射物内划定一个边界，在该边界以下，超新星 Iax 和正常超新星 Ia 的物理性质有所不同。我们的结果表明，SN 2014dt 与弱爆燃爆炸模型一致，该模型留下了束缚残余物，并驱动光学厚的准稳态风，在后期形成了光球线。数据还表明，这种风可能会在过去 450 天之后减弱，这可能表明放射性能量源已经衰变。
Type Iax supernovae (SNe Iax) are the largest known class of peculiar white dwarf SNe, distinct from normal Type Ia supernovae (SNe Ia). The unique properties of SNe Iax, especially their strong photospheric lines out to extremely late times, allow us to model their optical spectra and derive the physical parameters of the long-lasting photosphere. We present an extensive spectral timeseries, including 21 new spectra, of SN Iax 2014dt from +11 to +562 days after maximum light. We are able to reproduce the entire timeseries with a self-consistent, nearly unaltered deflagration explosion model from Fink et al. using TARDIS, an open source radiative-transfer code. We find that the photospheric velocity of SN 2014dt slows its evolution between +64 and +148 days, which closely overlaps the phase when we see SN 2014dt diverge from the normal spectral evolution of SNe Ia (+90 to +150 days). The photospheric velocity at these epochs, ∼400–1000 km s−1, may demarcate a boundary within the ejecta below which the physics of SNe Iax and normal SNe Ia differ. Our results suggest that SN 2014dt is consistent with a weak deflagration explosion model that leaves behind a bound remnant and drives an optically thick, quasi-steady-state wind creating the photospheric lines at late times. The data also suggest that this wind may weaken at epochs past +450 days, perhaps indicating a radioactive power source that has decayed away.